LOS ANGELES, California (CNN) -- An autopsy on the body of Donda West, mother of hip-hop mogul Kanye West, was inconclusive pending the results of toxicology tests, a spokesman for the Los Angeles County Coroner said Tuesday.
Ed Winter said preliminary reports indicated that West, 58, may have died from complications from cosmetic surgery. Beverly Hills plastic surgeon Jan Adams said he performed cosmetic surgery on her Friday at a surgical center.
West died Saturday evening after she was found unresponsive and in respiratory distress at her home, Winter said.
"She was taken to Centinela Freeman Regional Medical Center in Marina del Rey," he said. "Efforts to preserve her life were unsuccessful. She was pronounced dead at 8:28 p.m."
A funeral for West is scheduled for November 20, a representative for Kanye West said. Watch latest on the death of Donda West »
Adams told TMZ.com that he performed a tummy tuck and breast reduction on West last week and that her death was unforeseen. But another Beverly Hills cosmetic surgeon said he had recently refused to perform a procedure on West until she had a medical clearance for a condition he feared could lead to a heart attack.
"The preliminary information we had indicated that she had several minor medical issues," Winter said, "but I can't comment on those." He also said she was taking medications, but could not comment on which ones and in what dosages pending the toxicology reports.
Winter also said West was in good condition before the surgery and that investigators are talking with Adams about the surgery. He did not say when the results of the toxicology tests would be available.
Adams told TMZ.com that West's death could have been caused by a heart attack, pulmonary embolism or massive vomiting. He said he consulted with her for months and she changed her mind several times about going forward with the surgery, TMZ.com said.
TMZ.com, like CNN, is owned by Time Warner.
Adams later released a statement through his publicist expressing his "deepest condolences to the West family at a very difficult time" but declined further comment.
"As a medical doctor practicing in this field, I hold sacred the bond of confidentiality that exists between a patient and doctor," he said. "Out of respect for the West family and in the absence of other verifiable information, any comment from me without first discussing that information with the family would be unprofessional."
Adams is the television host of Discovery Health's "Plastic Surgery: Before and After." According to his biography on Discovery.com -- which has been removed from the Web site -- Adams is also the author of "Everything Women of Color Should Know About Cosmetic Surgery." He graduated from Harvard University, attended Ohio State University College of Medicine and studied plastic surgery at the University of Michigan.
On Monday, Beverly Hills cosmetic surgeon Andre Aboolian said through his publicist that Donda West consulted him in June about a procedure. Publicist Jo-Ann Geffen said West contacted Aboolian again two weeks ago to say she was ready to go forward, but Aboolian said he needed a medical clearance before he would perform the surgery.
"I always insist on a medical clearance for women over 40, and in this instance it was particularly important because of a condition she had that I felt could have led to a heart attack," Aboolian said, according to Geffen's statement.
Geffen said West was scheduled to see an internist for the appropriate tests, but did not keep the appointment.
Donda West was a major influence on her son's life, as the music producer-singer-songwriter has often said -- including in lyrics to some of his songs. She regularly attended her son's concerts, and was at his performance at the MTV Video Music Awards in September.
Earlier this year, she released a book she co-authored called "Raising Kanye: Life Lessons From the Mother of a Hip-Hop Superstar."
West retired from her post as professor and chair of the English Department at Chicago State University in 2004 to become her son's manager, according to the Kanye West Foundation Web site. She also became CEO of Super Good, the parent company of Kanye West Enterprises.
In Kanye West's song "Can't Tell Me Nothing," a track from his latest album, "Graduation," he rhymes about her attempt to discourage him from spending money on jewelry. On "Touch the Sky," from his 2005 album, "Late Registration," he recalls how his mother drove him from Chicago to New York in a U-Haul van.
Donda West was also the inspiration for the song "Hey Mama."
A statement issued late Monday from "Kanye West, his family and friends" thanked "everyone for the outpouring of support" and asked that in lieu of flowers, donations be made to the Kanye West Foundation, which Donda West co-founded with her son.
West, who is in Europe preparing for a tour of the continent, will remain overseas until next week, when he will return for the funeral, the representative said. The tour has been postponed. E-mail to a friend
CNN's Karen Bonsignore, K.J. Matthews and Lola Ogunnaike contributed to this report.